For the last month or so I've been focused in on the bass regulator as I struggle to make a good reed for it. But aside from the reed problems, I got to thinking about the air supply. It seems to me that there must have been some good reason for fitting the bass regulator so that it's air supply comes through the stock - but it seems to me that this design must also throw up some problems, relating to overall efficiency of the set. As I see it, this additional back pressure fed back from the bass regulator through the stock connection and back through the stock to the bag stock outlet can't be desirable and must have some effect on the overall balance and response of the set.

So this got me thinking that it might be better overall, if the bass regulator was connected to the bag with its own separate air supply feed directly to the windcap, just like the chanter. So in that case I would have a bag with two necks - a shorter one feeding the bass regulator from below my bag arm. I seem to have a vague memory of a film of Seamus Ennis playing a set with some kind of air tube direct to his bass regulator, along the same lines as I have suggested. Of course if this alteration was made to an existing set, the airway connection between the bass regulator and the stock would be sealed off. Then the back pressure produced by the bass regulator would be fed back directly into the bag, with much less impact on the other drone and regulator reeds within the stock.

I am not sure how your Bass regulator air feed is achieved ( or who made your pipes ) but if it has a Hollow Mainstock there is a seperate tube which independantly supplies the Bass. Some solid mainstocks ( all perhaps) have the air feed for the Bass reg. taken from the Middle regulator port. The independant air feed of a hollow stock combined with the long air passage through the seperator should eliminate back pressure problems.

Having said that I'll add that the Bass regulator, and the perfect working of same , as such is asking an awfull lot from an otherwise ridiculous instrument design. Where the chanter is played with various pressures to achieve a two (or more) octave range and the regulators are supposed to remain in the low octave and stay 'in tune' and the additional ' strapped on the side' tube is to give notes an octave below the chanter and also not jump pitch or sound like a fog horn.... aggghhhhh! Tis asking almost too much of the reedmaker!

My set has a solid stock - which I do like for other reasons. But the air supply for the bass regulator branches off from the baritone regulator feed. Of course a certain amount of back pressure is to be expected, but I think that when they added the bass regulator into the mix, it wasn't the best plan.

If this additional back pressure from the long bass regulator tube could be fed directly back to the bag, I think that this would be helpful in terms of overall performance. This back pressure isn't a constant - it will fluctuate a lot if the bass regulator is being used. And these fluctuations must have an effect on air pressure within the stock and therefore on the reed response of the drones and the other two regulator reeds. If a steady pressure is needed anywhere, it is within the stock.

If the bass regulator had its own air feed direct from the bag, then this specific back pressure would be much less of an issue. It would be diffused within the greater volume of the bag and I would think that the effect would be barely noticeable as the bag arm is already coping with the much more subtle pressure demands of the chanter reed.

Having said all this - the proof of the pudding would be in the eating. The best test would be to take an existing set and convert the bass regulator to a windcap only air feed. The main obstacle - and I think this was the real reason why makers didn't take this route in their early designs - is that a bag would have to be made with a third air outlet. This of course would involve changing the old bag template - everyone hates change and nobody wants more work. But if a thing's worth doing...

Well, the bass reg air feed from the Baritone reg hole should not affect the drones as they are not in the same chamber. The original mainstock designs of the developed full set were of the hollow type and the air for the bass comes direct from the bag, albeit from the same entry point as the wind for the rest of the body. The simpler option of using a solid stock and drilling into the reed chamber of the Baritone regulator probably does not cause any great problems with turbulances and fluctuations of pressure, makers have been doing this for a long time . But it could be possible that there is too much resistance to air flow going into the bass regulator for some reason.

It is all a matter of getting everything to balance; within the comfort zones of playability and tonality.

But even with the hollow stock design which you describe - where the bass regulator has it's own separate air feed tube within the stock, the back pressure from the bass regulator will still be an issue at the bag to stock outlet - the point being that this is the specific point where air pressure meets the reeds within the stock. I agree entirely that the aim should be to achieve the best balance - in terms of airflow and pressure as possible. But if a set is well balanced in the 3/4 form then
it makes sense to find the best way of adding in the bass regulator without upsetting this 'nice' balance.

I think that in many cases full sets are balanced around the bass regulator - but that is not the way I would like to go. In my opinion when a bass regulator is added to a set, it should be balanced in to sound in conformity with the desired drone pressure. That is to say - there should not be any major additional arm pressure coming in to play whenever a bass regulator key is touched.

Has it in fact got an adequate supply of air - i.e. feed hole from Baritone regulator bore, has the leather gasket between the attachment plate and main stock been squashed so it has spread partially covering the exit hole from main stock, is the air passageway in the separator big enough and clear of obstruction.

There is nothing unusual with the build or airflow of my own set. It was built in accordance with a long-established design and works fine within those limits, just like many other such full sets. My thoughts are on bass regulators in general and specifically their air supply - and how it might be possible to find a better way by means of an air supply directly from the bag to the windcap of the bass regulator, as I have proposed.

I'm not an expert on the history of the instrument, but it would seem possible that some maker might have connected their bass regulator to the bag in just this way. Although it would require the addition of another air outlet to the bag and an air inlet on the bass regulator windcap, the stock and the regulator itself would require much less work as there would be no airway cut between them.